Lubricant composition



Patented Mar. i7, 1Q42 2,276,453 LUBRICANT COMPOSITION No Drawing.Application July 14, 1939, Serial No. 284.444

4 Ciaims.

This invention relates to lubricant compositions; more particularly tolubricant compositions for usein the pressure forming of pulverizedmaterials into compact bodies, and to methods for making suchcompositions.

An object of this invention is the provision of an improved compositionfor use as a lubricant on material forming apparatus, and efficientmethods for compounding such compositions.

The composition provided by this invention is especially adapted to theproduction of magnetic cores of the well known insulated dust type. Inthe manufacture of these cores small particles of magnetic metal oralloy are coated with a suitable binder and then compressed into a body.In the usual compressing operation a measured quantity of the coatedparticles are placed in a die cavity, compacted with a forming memberforced into the cavity at high pressure, and finally removed from thecavity in theform of a composite body or core. For many core types avery high forming pressure is required and values in excess of 200,000pounds per square inch are employed regularly.

During the compressing operation the binder covered metal particles tendto bond themselves to the walls of the di and it is desirable to usesome preventive agent on the die members to avoid this action. Thelubricants that are ordinarily used on material forming operations, suchas mineral oil or grease, are not satisfactory for this purpose and anagent having unusual properties is required on dust core forming.apparatus to prevent the above described bonding action under thesubstantial forming pressures normally employed and the highly abrasiveaction of the metal particles in motion. The action of the protectiveagent becomes more criticalas the size of the metal particles used forthe cores is reduced and agents that are usable for pressing relativelycoarse particles are not successful when used with finer particles.Particles around 120 mesh in size and coarser have been pressed withzinc st-earate or petrolatum as a die coating. However, many cores aremade with dust that is 400 mesh in size and smaller, and these prioragents are not suitable with the finer dust because the fine particlesbecome cemented to the die members under pressure and the cores crack onremoval from the die. 'Another important foreign materials in the corebody is to be avoided because of their influence on the magnetic andelectrical properties of the completed core.

In accordance with this invention, a composition that is suitable foruse with all sizes of particles .is provided by compounding stearicacid, spermaceti, lanolin, borax and water into a pastelike mass oremulsion. The composition is spread in a thin coating or layer on thewalls of the die cavity amion the forming member before the particlesare placed in the cavity and the composition facilitates compression ofeven the finest dust into a core having high mechanical strength andgood service properties.

, For use in forming cores from fine insulated dust particles, thefollowing composition gives the best results:

' Parts by weight Stearic acid 25 Spermaceti 5 Lanolin 5 Borax 2 WaterHowever, some variation in the above ingredient proportionsispermissible and in general the following ranges are satisfactory:

Parts by weight Stearic acid 20 to 30 Spermaceti 4 to 6 Lanolin 4 to 6Borax 1 to 3 Water 25 to The necessary uniformity can be provided byfirst mixing the stearic acid and spermaceti in the form of smallpieces, then adding molten lanolin, and finally adding the borax inwater solution. In one satisfactory procedure the proferred compositionwas prepared as follows: Twenty-five pounds of stearic acid and fivepounds of spermaceti were shredded into small chips and thoroughly mixedtogether. The five pounds of lanolin were heated to a temperatureslightly above the melting point and then poured slowly into the mixedchips. The mixture was stirred during the addition of the molten lanolinto effect its thorough distribution. The two pounds of borax weredissolved in 30 pounds of water, with the aid of gentle heating. Theborax solution was then heated to a temperadie surfaces.

sistency, and its viscosity is affected by the, proportion of waterused. Variations in consistency that may be desired for different fieldsof service.

can be secured by changes in the proportion of water, employed, but inall cases an adequate quantity of water should be used and sufiicientagitation applied both during and after the actual mixing operation toinsure formation of. a homogeneous emulsion. 4

The above proportions and process provide a composition that isespecially suitable for use in pressing fine insulated metal particlesinto magnetic cores. The consistency of this particu-- lar compositionis suitable for convenient application on the surface of the forming diecavity and film to the'die members, very little of the com- 7 positionis incorporated in the core body and compressing member by means of astiff brush or rubber paddle. Subsequent wiping with a soft clothremoves excess composition and spreads the film evenly on the diemembers. As the dust particles are compressed in the cavity, thecompound forms a continuous and tough film which efiectively resists theabrasive action of the moving particles and facilitates the necessaryshifting of the outer strata of particles adjacent to the The filmwithstands the frictional heat developed during compression of the dustand adheres to the die members with the result that the completed coreis readily removed from the cavity without any straining or cracking ofthe core. Due to the close adherence of the due to the properties of thecomposition ingredients, this addition does not detract from the normalelectrical or magnetic qualities of the core.

It will be apparent that some modifications of the above specificallydescribed composition and process can be adopted to meet particularconditions, and it is to be understood that the invention is limitedonly by the scope of the appended claims.

What is claimed is:

1. A composition suitable for lubricating die members used incompressing finely divided particles of material into composite bodies,comprising to 80 parts 'stearic acid, 4 to 6 parts spermaceti, 4 to 6parts lanolin, 1 to 3 parts borax, and a suflicient quantity of water toform a homogeneous emulsion of said ingredients.

2. A composition for lubricating die-members used in compressing finelydivided particles of material into composite bodies, comprising partsstearic acid, 5 parts spermaceti, 5 parts lanolin, 2 parts borax, and asufficient quantity i of water to form a homogeneous emulsion of saidingredients.

3. A composition suitable for lubricating die members used incompressing finely divided particles of material into composite bodiescomprising from 20 to parts stearic acid, 4 to 6 parts spermaceti, 4 to6 parts lanolin, l to 3 parts borax, and 25 to parts water.

4. A lubricating composition comprising 25 parts stearic acid, 5 partsspermaceti, 5 parts lanolin, 2 parts borax, and 25 parts water.

ADOLPH F. BANDUR.

